How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. This sensor is located on the outside of the transmission, above the flywheel gear. It sends a signal to the ECU via a grey wire (T55/49) which is then sent to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, above the flywheel ring. The sensor sends an electrical signal through the grey wire to pin T55/49. The ECU then uses this information to control fuel, timig and boost. It also sends signals to the G5 Tachometer located in the instrument cluster.
The sensor is used to connect with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft reached TDC and also the location of the camshaft so that it can activate the spark and injectors.
If this sensor fails, the ECU will display a P00160 error code. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate an issue with the chain or a jumpy chain link in the upper chain of timing. The code will not appear without the additional information supplied by other sensors (G4 or G40).
It is a little tricky to test since there are several connector pins, and each one has different functions. The best method for doing this is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms when the sensor is in full operation. Check for signs of coolant or oil in the connector bay if there are problems with this part.
2. Injectors
Yesterday accelerating full speed from highway paytoll, I experienced a big cut in power as if the engine was running out of gas or injectors aren't firing anymore. I took out the spark plugs this morning, three were soaked in gasoline, and the fourth was dry. When I crank the engine with no sparks, i place a tissue on top of each injector hole, the 3 drenched with gazoline leap out, however the 4th one stays closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got zero ohm. I'm assuming that the issue is elsewhere.
I also tried to reset the PID but with no luck. The car is able to start when the G28 is disconnected and runs fine when it is plugged in, but still has the intermittent misfire issue at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature value of -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is zero.
I'm not sure what to do. I believe that I've ruled everything else out. I'm afraid i may have missed something. Let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter is identical to the G4 and both function in the 80 100, 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or at a parts store. It is simple to test them - just put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector end facing up). They must be infinite ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to know the position and speed of the crankshaft to determine timing of fuel injectors, etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either one of these, the diagnostic scanner will display codes that could lead to the engine shutting down.
The signs of a failed G28 sensor include an inaccurate rev here counter in the gearbox the gears are shifting faster than normal and/or misfiring when you are in gear. If you experience any of these issues, it is most likely that your sensor is failing and needs replacing. They're cheap and easy to find, especially in the case of a Bosch model like ours. Alternatively, the GM version of this component is also a good choice.
5. Tachometer
A failing engine speed sensor could be the cause of numerous issues in your vehicle. It's an essential component of the transmission in your Audi since it sends information to the ECU regarding how fast or slowly the engine more info of the get more info car is turning. When this sensor fails, it could affect the performance of the transmission as well as the other car's components.
The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It sends an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU then processes this signal to control fuel, timig, and boost and then transmitting it to the G5 more info Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. Also, you can examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 as well as pin T26a/12. There should be the resistance to be around 1000 ohms between these points. This is a here standard component across the Audi 80 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.